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Summary

Summary

1.1 History of the flight

1.1.1 Overview

On 26 October 2003, at about 1346 Eastern Standard Time, a Boeing 767-238 aircraft, registered VH-EAL, with two pilots, seven cabin crew and 207 passengers, took off from Coolangatta Airport, Queensland, on a scheduled regular public transport service to Sydney, NSW. The aircraft had arrived at Coolangatta earlier that day, having flown the first sector from Sydney to Coolangatta. Shortly after takeoff, passing through an altitude of about 800 ft, the aircraft encountered heavy rain, hail and windshear. The crew reported that they increased thrust in accordance with the operator's published windshear escape manoeuvre. During the windshear encounter, the aircraft descended about 130 ft and a ground proximity warning system (GPWS) Mode 3 aural alert 'DON'T SINK' sounded.

During the subsequent climb, the cabin crew reported to the flight crew that there was damage, in the form of dents, to the leading edges of the wings. After diverting out to sea around the weather, the flight continued to Sydney. The crew configured the aircraft early in the approach to Sydney, in the event of flap and leading edge device extension difficulties due to the damage, however an uneventful landing was conducted.

1.1.2 Sequence of events

Time Event
0145 The Bureau of Meteorology (BoM) issued a terminal aerodrome forecast (TAF) for Coolangatta, valid for the period 0400 to 2200 on 26 October. The TAF was a statement of meteorological conditions expected for a specified period in the airspace within a radius of 5 NM of the reference point for Coolangatta Airport. It indicated temporary periods of less than one hour of rain and thunderstorms with associated wind gusts to 35 kts during the period 1400 to 1800 on 26 October, with a requirement for either 60 minutes holding during that period, or diversion to an alternate aerodrome.
0823 The BoM issued an amended TAF for Coolangatta aerodrome, valid for the period 1000 26 October to 0400 27 October. The indications for rain, thunderstorms and holding were unchanged.
0945 The BoM forecasting team met to discuss the developing situation and TAF requirements for thunderstorm activity for Brisbane Airport were brought forward to 1400.
1250 The BoM issued an Airport Warning for Coolangatta Airport indicating that thunderstorms were expected to affect the aerodrome from 1400.
1310 Coolangatta Automatic Terminal Information Service (ATIS) Echo was issued by Air Traffic Services (ATS). It included information on current wind direction and speed, cloud and visibility. The content of ATIS Echo is discussed at paragraph 1.9. It indicated no adverse weather conditions at Coolangatta.
1322 The BoM issued a report warning of significant meteorological activity (SIGMET) for the Brisbane Flight Information Region, valid from 1300 to 1900, which warned of a line of active thunderstorms from Dalby to Stanthorpe moving east at 30 kts.
1328 A Boeing 767 aircraft landed on runway 32 at Coolangatta.
1330 The BoM radar imagery indicated a thunderstorm developing very rapidly, ahead of the main line of thunderstorms, to the north-west of Coolangatta and starting to move south-east in a direction at least 30 degrees to the right of the average direction of the storm line.
1330:03 A Boeing 737 aircraft was cleared for takeoff from runway 32 at Coolangatta.
1330:24 EAL was issued an airways clearance.
1332:11 An Airtrainer CT4 aircraft was cleared to land on runway 35 at Coolangatta.
1336 The BoM reported that forecasters first became aware of the severity of the thunderstorm involved in the occurrence at about 1336. The storm continued to intensify and quickly moved to the Coolangatta area.
1338:22 Coolangatta ATIS 'Foxtrot' was issued. It included information on current wind direction and speed, cloud and visibility, and advice of rain and thunderstorms. The content of ATIS Foxtrot is discussed at paragraph 1.9.
1338:27 A Raytheon Beech 200 Super King Air aircraft was cleared to land on runway 35 at Coolangatta.
1339:07 The crew of EAL requested taxi clearance and reported in receipt of ATIS Echo.
1340 The BoM subsequently advised that the thunderstorm passed over Coolangatta aerodrome between about 1340 and 1349.
1343 The Coolangatta Tower controller advised the approach controller that visibility at Coolangatta was 2000 m in heavy rain.
1345:00 EAL was cleared for takeoff from runway 32 and assigned a departure heading of 060 degrees at 2 DME.
1346:49 The crew of EAL advised the Coolangatta Tower controller that they had stopped the turn and were heading 030 degrees due to weather.
1347:51 The crew of EAL requested that Approach advise Coolangatta Tower that they encountered heavy rain and hail on departure from runway 32.

1.2 Injuries to persons

No injuries to persons were reported.

1.3 Damage to aircraft

A post-flight technical examination revealed substantial damage to the leading edge slats, leading edge wedge panels, horizontal stabiliser, vertical stabiliser, radome, fuselage area above the pilots' windows, nose-cowls of both engines and fan blades on both engines (see Figures 1 and 2).

1.4 Other damage

Nil.

1.5 Personnel information

1.5.1 Pilot in command

Type of licence: Air Transport Pilot (Aeroplane) Licence
Medical certificate: Class 1
Flying experience (total hours): 11,126
Hours on the type: 5,156
Hours in the preceding 30 days: 47

1.5.2 Copilot

Type of licence: Air Transport Pilot (Aeroplane) Licence
Medical certificate: Class 1
Flying experience (total hours): 3,614
Hours on the type: 924
Hours in the preceding 30 days: 52

Both pilots last completed windshear training as part of the operator's recurrent training matrix during the period December 2002 to January 2003.

1.6 Aircraft information

Manufacturer: Boeing Commercial Airplane Group
Model: 767-238
Serial number: 23306
Registration: VH-EAL

1.6.1 Aircraft weather radar information

The aircraft was fitted with a Collins WXR-700X weather radar system, which did not include a windshear warning or a predictive windshear warning function. The weather radar display was superimposed on the aircraft navigation displays and indicated rainfall intensity in different colours, with green depicting light precipitation, yellow medium precipitation and red or magenta heavy precipitation. The radar manufacturer's documentation stated that red was equivalent to a rainfall rate of 12.7 to 50.8 mm per hour, indicating a storm category of 'strong to very strong'.

Specific guidance on the use of the weather radar was provided to crews in the operator's Flying Manual and a training CD-ROM. A document was also provided to crews on the operator's intranet site. Use of the weather radar was covered as part of the operator's recurrent training matrix.

The crew reported that the weather radar was set according to the operator's requirements for takeoff. During taxi, and the time taken to negotiate a departure heading with ATS, the crew scanned the weather ahead of the aircraft flight path. They reported areas of red on the display, with no hooks, fingers, contours, scalloped edges or U-shaped returns that could have indicated the presence of hail. They reported that they consequently assessed the areas of red on the weather radar display as heavy rain only.

1.7 Meteorological information

1.7.1 Prevailing weather conditions during the afternoon of the occurrence

An intense surface trough was moving across the south-east inland of Queensland, towards the south-east corner and was forecast to move off the south coast by about 1800 to 1900. The atmosphere was very unstable ahead of the trough and scattered to widespread showers and thunderstorms were forecast from about 1400. Computer model output and morning temperature and moisture profiles, obtained from weather balloon flights, indicated very favourable conditions for the development of thunderstorms, and the possibility of associated severe weather phenomena.

During the afternoon, the BoM issued a number of amended forecasts and warnings including area forecasts (ARFORs), TAFs and Airport Warnings for Coolangatta. Those forecasts included reference to thunderstorm activity expected to affect Coolangatta aerodrome after 1400. The Airport Warning for Coolangatta, issued at 1250, indicated that the thunderstorms may produce strong wind gusts and large hail. A SIGMET for the Brisbane Flight Information Region, valid from 1300 to 1900, was issued to warn of a line of active thunderstorms from Dalby to Stanthorpe moving east at 30 kts.

The aircraft operator provided the crew with a meteorological briefing package prior to departure from Sydney. In addition, the crew reported discussing the meteorological situation with the BoM meteorologist, positioned in the operator's flight dispatch organisation, prior to departure from Sydney. Further, they were aware of the line of storms to the west and south-west of Coolangatta, having negotiated past them during the first sector from Sydney to Coolangatta. During the turn-around at Coolangatta, the crew updated the Sydney TAF using the aircraft communications addressing and reporting system (ACARS) and obtained Coolangatta ATIS Echo.

The operator reported that the meteorologist was aware of the development of the thunderstorm in the vicinity of Coolangatta Airport, from the weather radar monitor located in the operator's flight dispatch area. That information was passed to the operator's port staff at Coolangatta, however, it was not passed to the crew of EAL, as the operator did not have a procedure for disseminating such information to crews once they had commenced taxiing.

1.7.2 Bureau of Meteorology - weather radar

The BoM received three-dimensional radar data for the Brisbane to Coolangatta area from weather radars located at Brisbane Airport and Marburg. The Marburg radar was situated on the Little Liverpool Range between Marburg and Rosewood about 50 km west of Brisbane.

The BoM reported that forecasters first became aware of the severe nature of the thunderstorm involved in the occurrence at about 1336. It continued to intensify and quickly moved to the Coolangatta area, passing over Coolangatta Airport between about 1340 and 1349. EAL was issued a takeoff clearance at about 1345. Images of the thunderstorm passing over Coolangatta at 1340 and 1350, including the aircraft flight path from takeoff to 10,000 ft, are depicted at Figures 3 and 4 respectively.

Two-dimensional images from BoM's weather radars were displayed at various air traffic control working positions by means of a PC-based system known within Airservices Australia as METRAD (Meteorological RADar) and within the military as RAPIC (RAdar PICture). The use of METRAD/RAPIC by Air Traffic Services (ATS) controllers is described at paragraph 1.17.1.

1.8 Aids to navigation

Not a factor in this occurrence.

1.9 Communications

All communications between ATS and the crew were recorded by ground based automatic voice recording equipment for the duration of the occurrence. The quality of the aircraft's recorded transmissions was good.

An ATIS broadcast provided advice of conditions pertaining to the operation of aircraft within 5 NM of the respective aerodrome reference point. Coolangatta ATIS Echo was current until 1337:41. ATIS Echo included runway 32 (active runway), wind from 350 degrees at 22 kts, crosswind maximum 15 kts, visibility greater than 10 km and three to four eighths of cloud at 2,500 ft.

At 1338:22 ATIS Foxtrot was issued. It included information to expect a VOR/DME approach, runway 32 wet, wind at 350 degrees at 20 kts, crosswind maximum 15 kts, visibility reducing to 5,000 m in rain and thunderstorms, five to seven eighths of cloud at 2,500 ft and one to two eighths of cloud at 1,500 ft.

At 1339:07, 45 seconds after ATIS Foxtrot was issued, the crew requested taxi clearance and advised having received ATIS Echo. The SMC controller did not advise the crew of the changed ATIS or provide them with the changed conditions.

1.10 Aerodrome information

Runway 32 at Coolangatta was sealed and level. It was 2,042 m long, 45 m wide and aligned on a magnetic heading of 319 degrees.

1.11 Flight recorders

The aircraft was equipped with a Honeywell solid state flight data recorder (FDR). The FDR data indicated that EAL encountered windshear at about 800 ft above ground level. The encounter lasted about 30 seconds and included an 11-second period where the aircraft descended, resulting in a total altitude loss of about 130 ft. The pitch attitude changed from about 20 degrees nose up to 6 degrees nose up during this period. A GPWS Mode 3 aural alert 'DON'T SINK' was recorded for 4 seconds. Take-off thrust was de-rated giving an engine pressure ratio (EPR) of 1.39 and the power setting did not vary during the event. The de-rate is equivalent to a thrust reduction of 9 per cent.

The recorded FDR data indicated that, throughout the windshear encounter, both EPR and thrust lever angle (TLA) remained in the take-off position until climb thrust was set when clear of the encounter.

Recorded FDR data, indicating aircraft pitch attitude and GPWS Mode 3 alert, is depicted at Appendix 1.

1.12 Wreckage information

Not a factor in this occurrence.

1.13 Medical information

The crew reported no physiological or medical condition that could have impaired their performance.

1.14 Fire

Nil.

1.15 Survival aspects

Not a factor in this occurrence.

1.16 Tests and research

Nil.

1.17 Organisational information

1.17.1 Air Traffic Services information

The manual of air traffic services (MATS) was a joint document of Airservices Australia and the Department of Defence. The manual was based on rules published by both those organisations and the Civil Aviation Safety Authority (CASA). Section 5.1.7 of MATS permitted ATS controllers to use the BoM PC-based METRAD/RAPIC two-dimensional weather radar displays, in conjunction with information obtained from other sources, to provide as much information that was available to crews on hazardous weather avoidance. Those displays, which were also available to the general public, were updated every 10 minutes and therefore, could have been up to 10 minutes behind the actual time. Coolangatta ATS reported that they had access to METRAD/RAPIC. ATS did not offer, nor did the crew request, weather information accessed from the METRAD/RAPIC display.

1.18 Additional information

1.18.1 Aircraft flight path information

After encountering the adverse weather, the crew reported that they stopped the cleared turn and attempted to divert around the conditions being experienced. ATS radar data indicated that the aircraft continued on easterly headings to about 70 NM east of the coast, before turning south towards Sydney. The crew was unable to regain the cleared flight-planned route.

1.18.2 Other aircraft movements

There were a number of other aircraft movements into and out of Coolangatta aerodrome preceding the occurrence flight. A Boeing 767 landed on runway 32 at 1328, a Boeing 737 took off from runway 32 at about 1330, a CT4 landed on runway 35 at about 1335 and a B200 Super King Air landed on runway 35 at about 1340. The landing aircraft had approached Coolangatta from the south. No reports of thunderstorm activity, heavy rain, hail or windshear were received from any of those aircraft, except to say that the line of storms was approaching from the west and south-west.

1.18.3 Previous similar occurrence

The occurrence involving EAL displayed a number of similarities to a Boeing 737 microburst encounter that occurred at Brisbane aerodrome on 18 January 2001 (see ATSB investigation report BO/200100213). As a result of that occurrence, the ATSB issued a number of safety recommendations to Airservices Australia, BoM and CASA. Those recommendations included, but were not limited to:

  • a review of air traffic controller initial and recurrent training programs to ensure they adequately addressed the effect of convective weather on aircraft performance and the limitations of airborne weather radar
  • expediting the introduction of an integrated weather radar/air traffic control radar video display system capable of providing multiple weather echo intensity discrimination without degradation of air traffic control radar information
  • an increased emphasis in air traffic controller training programs to ensure that all appropriate sources of information, such as meteorological forecasts, controller observations, radar information, and pilot reports are provided to flight crews
  • development of a standard scale of thunderstorm intensity for use within the aviation industry
  • BoM meteorologists to act as focal points for liaison with air traffic control units.
  • As a result of the occurrence and safety recommendations, the following safety actions were implemented:
  • Airservices Australia produced a hazardous weather training program for its air traffic controllers
  • with the assistance of BoM and the radar manufacturer, the operator produced a CD-ROM based weather radar training program for issue to its crews
  • the operator included information regarding operation of the weather radar and flight in heavy rain in its Flying Manual
  • BoM integrated a qualified meteorologist into the operator's flight dispatch organisation.

1.19 New investigation techniques

Not relevant in this occurrence.

 
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